WO1992017759A1 - Method of testing performance of device for measuring physical quantity by using change of distance between electrodes and physical quantity measuring device provided with function of executing this method - Google Patents

Abstract

A fixed base plate (10) having a rigidity and a flexible base plate (20) are so provided as to face each other. The peripheries of both the base plates are fixed on a casing (40) of a device. An acting body (30) is bonded to the lower surface of the flexible base plate. Testing electrodes (11t, 13t, 15t) are formed on the lower surface of the fixed base plate and further fixed electrodes (11, 13, 15) are formed under the testing electrodes via an insulation layer (16). Displacement electrodes (21, 23, 25) are formeed on the upper surface of the flexible base plate. When an acceleration acts on the acting body, the flexible base plate bends and the distances between the fixed electrodes and the displacement electrodes changes, causing the capacitance between the electrodes to change. The acted acceleration can be measured by measuring the capacitance changed. For testing the performance of the device, a Coulomb force is made to act on the testing electrodes and the displacment electrodes by applying voltages across both the electrodes. The flexible base plate is bent due to the Coulomb forces and there is the same state as the one when the acceleration acts. The testing of the performance becomes possible by measuring the change of the capacitance between the fixed electrodes and the displacement electrodes in this state.

Description

Description Operation test method for a device that detects a physical quantity by using a change in the distance between electrodes, and a physical quantity detection device having a function of performing this method.Technical field The present invention uses a change in the distance between electrodes. In addition to the method for testing the operation of a device that detects physical quantities such as force, acceleration, and magnetism, it also detects the physical quantities such as force, acceleration, and magnetism that have the function of performing this operation test method. Related to equipment. Background Technology In the automotive and mechanical industries, there is a growing demand for detection devices that can accurately detect physical quantities such as force, acceleration, and magnetism. In particular, there is a demand for a small device capable of detecting these physical quantities for each two-dimensional or three-dimensional component. To meet such demands, gauge resistance is formed on a semiconductor substrate such as silicon, There has been proposed a force detection device that converts mechanical strain generated in a substrate based on a force applied from a substrate into an electric signal using a piezoresistance effect. If a weight is attached to the detection part of this force detection device, an acceleration detection device that detects acceleration applied to the weight as a force can be realized, and if a magnetic material is attached, the magnetism acting on the magnetic material is As a result, it is possible to realize a magnetic detection device that performs the detection. For example, U.S. Pat.Nos. 4,905,523, 4,969,605, and 4,969,366 describe the forces and accelerations according to the inventor's invention. A magnetic detection device is disclosed. Instead of the above-described detection device using the piezoresistance effect, a detection device using a change in the distance between electrodes has been proposed. For example, Japanese Patent Application No. 2-2742499 describes a detection device having a simple structure in which two substrates are arranged to face each other and electrodes are formed on each substrate. It has been disclosed. In this detection device, one of the substrates is displaced based on a physical quantity such as force, acceleration, or magnetism to be detected, and the displacement changes the distance between the electrodes formed on the two substrates. Detected as a change in capacitance. Alternatively, a method is disclosed in which a piezoelectric element is sandwiched between both electrodes, and a change in the distance between the electrodes is detected as a voltage generated by the piezoelectric element. If an external force is directly applied to one of the substrates to cause displacement, it functions as a force detecting device for detecting the applied external force. In addition, if a weight is joined to one of the substrates and the substrate is displaced based on the acceleration acting on the weight, it functions as an acceleration detecting device that detects the applied acceleration. In addition, If a magnetic body is bonded to the substrate and the substrate is displaced based on the magnetism acting on the magnetic body, it functions as a magnetism detecting device for detecting the magnetism acting.

 Generally, when a detection device of some kind of physical quantity is commercialized, it is necessary to perform an operation test to determine whether or not this detection device outputs a correct detection signal. Conventionally, such an operation test employs a method in which a physical quantity to be detected is actually applied to the detection device, and a detection signal at that time is examined. For example, in the case of an acceleration detection device, an acceleration of a predetermined magnitude is actually applied to the detection device from a predetermined direction and the detection signal at that time is correct according to the applied acceleration. It will be determined whether or not. However, in order to perform such an operation test, dedicated test equipment is required, and the test operation is also complicated and time-consuming. In particular, the quantity that can be tested with dedicated test equipment is limited, which leads to reduced productivity. Therefore, such conventional test methods are unsuitable as operation tests for mass-produced devices.

A first object of the present invention is to provide a method capable of performing a simple operation test on an apparatus for detecting a physical quantity by utilizing a change in the distance between electrodes, and a second object is to provide a method for performing this simple operation. An object of the present invention is to provide a detection device having a function of performing a self-diagnosis by a simple operation test method. Disclosure of the invention

<Operation test method>

 The operation test method according to the present invention includes a displacement electrode supported so as to be capable of being displaced by the action of an external force, a fixed electrode fixed to a device housing at a position facing the displacement electrode, and a distance between the two electrodes. It is equipped with a detection means for extracting changes as an electric signal, and is used to perform an operation test of a detection device for detecting a physical quantity corresponding to an external force as an electric signal. It can be grasped separately.

 (1) In the first method of the operation test according to the present invention, a predetermined voltage is applied between the fixed electrode and the displacement electrode, and the displacement electrode is displaced by Coulomb force generated based on the applied voltage. In this displacement state, the operation of the detecting device is tested by comparing the electric signal detected by the detecting means with the applied voltage.

(2) In the second method of the operation test according to the present invention, a test electrode fixed to the device housing at a position facing the displacement electrode is further provided, and a predetermined voltage is applied between the test electrode and the displacement electrode. Is applied, and the displacement electrode is displaced by a cooler generated based on the applied voltage. By comparing the electric signal detected by the detecting means with the applied voltage in this displaced state, the operation of the detecting device is tested. It is the one that was made. (3) In a third method of the operation test according to the present invention, a test electrode supported so as to be displaceable together with the displacement electrode is further provided, and a predetermined voltage is applied between the test electrode and the fixed electrode. The displacement electrode is displaced by the Coulomb force generated based on the applied voltage, and the operation of the detecting device is tested by comparing the electric signal detected by the detecting means with the applied voltage in this displaced state. It is something to do.

 (4) The fourth method of the operation test according to the present invention comprises the steps of: a first test electrode supported so as to be displaced together with the displacement electrode; and a device housing at a position opposed to the first test electrode. And a fixed second test electrode, and a predetermined voltage is applied between the first test electrode and the second test electrode, and the displacement electrode is generated by Coulomb force generated based on the applied voltage. The operation of the detection device is tested by displacing and comparing the electric signal detected by the detection means with the applied voltage in the displaced state.

<Application to capacitance detection device>

 According to the present invention, by applying the above-described operation test method to a physical quantity detection device of a type that detects a change in electrode spacing as a change in capacitance, the following method having a self-diagnosis function is provided. Three detection devices can be realized.

(1) The first detection device has a fixed portion fixed to the device housing, an action portion that receives a force based on the action of a physical quantity such as external force, acceleration, magnetism, and the like, Between A flexible substrate having a flexible portion formed and flexible; a fixed substrate fixed to the device housing so as to face the flexible substrate;

 A displacement electrode formed at a position where displacement occurs due to the radius of the flexible substrate;

 A fixed electrode fixed by the fixed substrate and formed at a position facing the displacement electrode;

 A test electrode fixed to the device housing at a position facing the displacement electrode, and electrically insulated from the fixed electrode;

 Detecting means for outputting a change in capacitance between the displacement electrode and the fixed electrode as an electric signal;

 Voltage applying means for applying a predetermined voltage between the test electrode and the displacement electrode;

 With

 The operation test can be performed by detecting the force acting on the action part based on the electric signal output from the detecting means, and comparing the electric signal output from the detecting means with the applied voltage applied by the voltage applying means. It is like that.

(2) The second detection device includes a fixed portion fixed to the device housing, an action portion that receives a force based on the action of a physical quantity such as external force, acceleration, magnetism, and the like, A flexible substrate having a flexible portion formed therebetween; and a fixed substrate fixed to the device housing so as to face the flexible substrate; A displacement electrode formed at a position where displacement occurs due to the radius of the flexible substrate;

 A fixed electrode fixed by the fixed substrate and formed at a position facing the displacement electrode;

 A test electrode supported so as to be displaceable with the displacement electrode, and electrically insulated from the displacement electrode;

 Detecting means for outputting a change in capacitance between the displacement electrode and the fixed electrode as an electric signal;

 Voltage applying means for applying a predetermined voltage between the test electrode and the fixed electrode;

 With

 The operation test can be performed by detecting the force acting on the action part based on the electric signal output from the detecting means and comparing the electric signal output from the detecting means with the applied voltage applied by the voltage applying means. It is the one that was adopted.

 (3) The third detection device includes a fixed portion fixed to the device housing, an action portion that receives a force based on the action of a physical quantity such as an external force, acceleration, magnetism, and the like. A flexible board formed between the flexible board and the flexible board, and a fixed board fixed to the device housing so as to face the flexible board;

 A displacement electrode formed at a position where displacement occurs due to the radius of the flexible substrate;

Fixed by the fixed substrate, at a position facing the displacement electrode A fixed electrode formed,

 A first test electrode which is formed at a position where the flexible substrate bends based on its own displacement and which is electrically insulated from the displacement electrode;

 A second test electrode fixed to the device housing at a position facing the first test electrode and electrically insulated from the fixed electrode;

 Detecting means for outputting a change in capacitance between the displacement electrode and the fixed electrode as an electric signal;

 Voltage applying means for applying a predetermined voltage between the first test electrode and the second test electrode;

 With

 The operation test can be performed by detecting the force acting on the action part based on the electric signal output from the detecting means and comparing the electric signal output from the detecting means with the applied voltage applied by the voltage applying means. It was made.

Application to piezoelectric detectors>

 Further, according to the present invention, the following three detection devices having a self-diagnosis function are applied by applying the above-described operation test method to a physical quantity detection device of a type that detects a change in electrode spacing using a piezoelectric element. Can be realized.

(1) The first detection device includes a fixed portion fixed to the device housing, an action portion that receives a force based on the action of a physical quantity such as an external force, acceleration, magnetism, and the like. Between A flexible substrate having a flexible portion formed and flexible; a fixed substrate fixed to the device housing so as to face the flexible substrate;

 A displacement electrode disposed at a position where displacement occurs due to bending of the flexible substrate;

 A fixed electrode fixed by a fixed substrate,

 A piezoelectric element which is arranged so as to be sandwiched between the flexible substrate and the fixed substrate, converts a pressure applied by both substrates into an electric signal and outputs the electric signal to both electrodes,

 A test electrode fixed to the device housing at a position facing the displacement electrode, and electrically insulated from the fixed electrode;

 A voltage applying means for applying a predetermined voltage between the test electrode and the displacement electrode;

 The operation test is performed by detecting the force acting on the action part based on the electric signal output from the piezoelectric element and comparing the electric signal output from the piezoelectric element with the applied voltage applied by the voltage applying means. It is something that can be done.

(2) The second detection device includes a fixed portion fixed to the device housing, an action portion that receives a force based on the action of a physical quantity such as external force, acceleration, magnetism, and the like, and a second portion including the fixed portion and the action portion. A flexible substrate having a flexible portion formed therebetween; and a fixed substrate fixed to the device housing so as to face the flexible substrate; A displacement electrode disposed at a position where displacement occurs due to bending of the flexible substrate;

 A fixed electrode fixed by a fixed substrate,

 A piezoelectric element which is arranged so as to be sandwiched between the flexible substrate and the fixed substrate, converts a pressure applied by both substrates into an electric signal and outputs the electric signal to both electrodes,

 A test electrode supported to be displaceable with the displacement electrode and electrically insulated from the displacement electrode;

 Voltage applying means for applying a predetermined voltage between the test electrode and the fixed electrode;

 With

 The operation test can be performed by detecting the force acting on the action part based on the electric signal output from the piezoelectric element and comparing the electric signal output from the piezoelectric element with the applied voltage applied by the voltage applying means. It was made.

 (3) The third detection device includes a fixed portion fixed to the device housing, an action portion that receives a force based on the action of a physical quantity such as an external force, acceleration, magnetism, and the like. A flexible substrate having a flexible portion formed therebetween; and a fixed substrate fixed to the device housing so as to face the flexible substrate;

 A displacement electrode disposed at a position where displacement occurs due to the radius of the flexible substrate;

A fixed electrode fixed by a fixed substrate, A piezoelectric element which is arranged so as to be sandwiched between the flexible substrate and the fixed substrate, converts a pressure applied by both substrates into an electric signal and outputs the electric signal to both electrodes,

 A first test electrode which is formed at a position where a radius is generated in the flexible substrate based on its own displacement and which is electrically insulated from the displacement electrode;

 A second test electrode fixed to the device housing at a position facing the first test electrode and electrically insulated from the fixed electrode;

 Voltage applying means for applying a predetermined voltage between the first test electrode and the second test electrode;

 With

 The operation test can be performed by detecting the force acting on the action part based on the electric signal output from the piezoelectric element and comparing the electric signal output from the piezoelectric element with the applied voltage applied by the voltage applying means. It is like that.

<Device that performs detection by difference>

 In another detection device according to the present invention,

 It has a fixed portion fixed to the device housing, an operating portion receiving a force based on the action of an external physical quantity, and a flexible portion formed between the fixed portion and the operating portion and having flexibility. A flexible substrate;

A first fixed substrate fixed to the device housing so as to face the first surface of the flexible substrate; A second fixed substrate fixed to the device housing so as to face the second surface of the flexible substrate;

 A first displacement electrode formed on the first surface of the flexible substrate, and a second displacement electrode formed on the second surface of the flexible substrate. The first displacement electrode is fixed by the first fixed substrate, A first fixed electrode formed at a position facing the displacement electrode,

 A second fixed electrode fixed by the second fixed substrate and formed at a position facing the second displacement electrode;

 The difference between the change in the capacitance between the first displacement electrode and the first fixed electrode and the change in the capacitance between the second displacement electrode and the second fixed electrode is calculated as Detection means for outputting as a signal;

 Is established,

 The force acting on the acting portion is detected based on the electric signal output from the detecting means. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side sectional view showing a basic structure of a capacitance type acceleration detecting device to which an operation test method according to the present invention is applied.

FIG. 2 is a bottom view of the fixed substrate 10 of the detection device shown in FIG. FIG. 1 shows a cross section of the fixed substrate 10 of FIG. 2 cut along the X-axis. FIG. 3 is a top view of the flexible substrate 2 in the detection device shown in FIG. FIG. 1 shows a cross section of the flexible substrate 20 of FIG. 3 cut along the X-axis.

 FIG. 4 is a side cross-sectional view showing a radiused state of the detection device when a force Fx in the X-axis direction acts on an action point P of the detection device shown in FIG.

 FIG. 5 is a side cross-sectional view illustrating a radius state of the detection device when a force Fz in the Z-axis direction is applied to an action point P of the detection device illustrated in FIG.

 FIG. 6 is a circuit diagram showing a circuit for operating the detection device shown in FIG. 1 and a circuit for performing an operation test on the circuit.

 FIG. 7 is a circuit diagram showing an example of a specific circuit configuration of the CV conversion circuit shown in FIG.

 FIG. 8 is a side cross-sectional view showing a specific test method for detecting a force in the + Z-axis direction.

 FIG. 9 is a side sectional view showing a specific test method for detecting a force in the Z-axis direction.

 FIGS. 10a and 10b are side sectional views of a capacitance type acceleration detection device having a function of performing a self-diagnosis by performing the operation test method according to the present invention.

FIG. 11 is a circuit diagram showing a circuit for operating the detection device shown in FIG. 1A and a circuit for performing an operation test on the circuit. FIG. 12 is a side sectional view of another capacitive acceleration detection device having a function of performing self-diagnosis by performing the operation test method according to the present invention.

 FIG. 13 is a side cross-sectional view of a capacitance-type force detection device having a function of performing self-diagnosis by performing the operation test method according to the present invention.

 FIG. 14 is a side sectional view of a piezoelectric acceleration detecting device having a function of performing a self-diagnosis by performing the operation test method according to the present invention.

 FIG. 15 is a top view showing the shape of an electrode formed on the upper surface of the piezoelectric element 45 in the detection device shown in FIG. FIG. 16 is a side sectional view of a piezoelectric force detection device having a function of performing a self-diagnosis by performing the operation test method according to the present invention.

 FIG. 17 is a side sectional view of another piezoelectric type force detecting device having a function of performing a self-diagnosis by performing the operation test method according to the present invention.

 FIG. 18 is a side cross-sectional view of an evening acceleration detection device that takes a difference in acceleration detection in all directions.

 FIGS. 19a and 19b are plan views showing electrode arrangements in the device shown in FIG.

FIG. 20 is a circuit diagram of a circuit for performing acceleration detection and operation test in the Z-axis direction in the device shown in FIG. FIG. 21 is a graph showing a general relationship between a distance d between electrodes of a capacitive element and a capacitance value C.

 FIG. 22 is a side sectional view showing another embodiment of the device shown in FIG.

 FIG. 23 is a side sectional view showing still another embodiment of the device shown in FIG.

 FIG. 24 is a side sectional view showing an embodiment in which the device shown in FIG. 18 is configured using metal.

 FIG. 25 is a side sectional view showing an embodiment in which the device shown in FIG. 24 is applied to a force detection device. BEST MODE FOR CARRYING OUT THE INVENTION

§ Basic structure of detector

Before describing the operation test method according to the present invention, the structure and principle of a detection device to which the present invention is applied will be briefly described. FIG. 1 is a side sectional view showing a basic structure of an acceleration detecting device to which the present invention is applied. The main components of this detection device are a fixed substrate 1, a flexible substrate 20, a working body 30, and a device housing 40. FIG. 2 shows a bottom view of the fixed substrate 10. FIG. 1 shows a cross section of the fixed substrate 10 of FIG. 2 cut along the X-axis. The fixed substrate 10 is a disk-shaped substrate as shown, and the periphery is fixed to the device housing 40. On this underside, Fixed electrodes 11 to 14 and a disk-shaped fixed electrode 15 are formed as shown in the figure. On the other hand, FIG. 3 shows a top view of the flexible substrate 20. FIG. 1 shows a cross section obtained by cutting the flexible substrate 20 of FIG. 3 along the line X. The flexible substrate 20 is also a disk-shaped substrate as shown in the figure, and its periphery is fixed to the device housing 4 #. On the upper surface, fan-shaped displacement electrodes 21 to 24 and a disk-shaped displacement electrode 25 are formed as shown in the figure. The action body 30 has a columnar shape as shown by the broken line in FIG. 3, and is coaxially joined to the lower surface of the flexible substrate 20. The device housing 40 has a cylindrical shape and fixedly supports the periphery of the fixed substrate 10 and the flexible substrate 20.

The fixed substrate 10 and the flexible substrate 20 are arranged at predetermined intervals at positions parallel to each other. Both are disc-shaped substrates, whereas the fixed substrate 1 ◦ has high rigidity and is hard to form a radius, whereas the flexible substrate 20 has flexibility and This is a substrate that produces only In the example shown in FIG. 1, the rigidity of the fixed substrate 1 ◦ is increased by increasing the thickness, and the flexibility of the flexible substrate 20 is increased by decreasing the thickness. By changing it, rigidity and flexibility may be provided. Alternatively, a groove may be formed in the substrate, or a through hole may be formed to provide flexibility. '' Fixed substrate 10, flexible substrate 20, working body 30 perform their original functions Any material may be used as long as the material can be used. For example, it can be made of semiconductor or glass, or can be made of metal. However, when the fixed substrate 10 and the flexible substrate 20 are made of metal, it is necessary to take a method such as forming an insulating layer between the electrodes so as not to short-circuit each electrode. Further, each electrode layer may be made of any material as long as it has conductivity.

Now, as shown in Fig. 1, an action point P is defined at the center of gravity of the action body 30, and an XYZ three-dimensional coordinate system with this action point P as the origin is defined as shown in the figure. That is, the X axis is defined in the right direction of Fig. 1, the Z axis is defined in the upward direction, and the Y axis is defined in the direction perpendicular to the paper surface toward the back side of the paper surface. Of the flexible substrate 20, the central portion on which the operating body 30 is mounted is referred to as an operating portion, the peripheral portion fixed by the device housing 40 is referred to as a fixing portion, and the portion therebetween is referred to as a flexible portion. In this case, when the acceleration is applied to the working body 30, the flexible portion is bent, and the working portion is displaced with respect to the fixed portion. Here, assuming that the entire detection device is mounted on, for example, an automobile, an acceleration is applied to the operating body 3 ° based on the traveling of the automobile. _C Due to the acceleration, an external force acts on the action point P. When no force is applied to the point of action P, as shown in Fig. 1, the fixed electrodes 11 to 15 and the displacement electrodes 21 to 25 and-maintain a parallel state at a predetermined interval. . Now, fixed electrode 1 1 15 and displacement electrodes 21 to 25 facing each other are referred to as capacitive elements C1 to C5, respectively. Here, for example, when a force Fx in the X-direction acts on the point of action P, this force FX generates a momentary force on the flexible substrate 2 °, and as shown in FIG. The substrate 20 will be bent. Due to this bending, the distance between the displacement electrode 21 and the fixed electrode 11 increases, but the distance between the displacement electrode 23 and the fixed electrode 13 decreases. Assuming that the force acting on the point of action P is —F x in the opposite direction, bending in the opposite relationship occurs. When the force F x or — F x acts in this way, a change appears in the capacitance of the capacitive elements C 1 and C 3. By detecting this, the force FX or — FX is obtained. Can be detected. At this time, the distance between each of the displacement electrodes 22, 24, and 25 and each of the fixed electrodes 12, 14, and 15 increases or decreases partially, It can be assumed that it does not change. On the other hand, when the force F y or one F y in the Y direction acts, the same applies only to the distance between the displacement electrode 22 and the fixed electrode 12 and the distance between the displacement electrode 24 and the fixed electrode 14. Changes occur. In addition, when the force Fz in the Z-axis direction acts, as shown in Fig. 5, the distance between the displacement electrode 25 and the fixed electrode 15 decreases, and when the car Fz in the opposite direction acts. This interval increases. At this time, the displacement electrodes 21-24 and the fixed electrode; Is also small or large, but the change in the distance between the displacement electrode 25 and the fixed electrode 15 is most remarkable. Wherein, the force F z or by detecting a change in capacitance of the capacitive element C 5 - it is possible to detect the F _Z. In general, the capacitance C of a capacitive element is given by: S = electrode area, d = electrode spacing, and dielectric constant £

 C = ε S / d

Is determined by Therefore, the capacitance C increases as the distance between the opposing electrodes decreases, and decreases as the distance between the electrodes increases. The detector uses this principle to measure the change in capacitance between each electrode, and based on the measured value,

It detects the external force acting on P, in other words, the applied acceleration. That is, the acceleration in the X 轴 direction is based on the capacitance change between the capacitive elements CI and C3, the acceleration in the Y-axis direction is based on the capacitive change in the capacitive elements C2 and C4, and the acceleration in the Z-axis direction is the capacitive element C Each detection is performed based on the capacity change of 5.

The present invention relates to an operation test method for a detection device based on such a principle. Although the above-described detection device is of a capacitance type, a piezoelectric detection device detects a change in capacitance by inserting a piezoelectric element between a flexible substrate and a fixed substrate. Instead, the voltage generated by this piezoelectric element is detected. § 2 Operation test method

Subsequently, an operation test method according to the present invention will be described. FIG. 6 is a circuit diagram showing a circuit for operating the detection device shown in FIG. 1 and a circuit for performing an operation test on the circuit. Here, the capacitance elements C1 to C5 correspond to the capacitance elements formed in the acceleration detection device described above. For example, the capacitance element C 1 is composed of a combination of a fixed electrode 11 and a displacement electrode 21. The CV conversion circuits 51 to 55 connected to the respective capacitance elements C 1 to C 5 have a function of converting the capacitance value C of each capacitance element into a voltage value V. Therefore, the voltage values V1 to V5 output from the CV conversion circuits 51 to 55 are proportional to the capacitance values of the capacitance elements C1 to C5, respectively. The differential amplifier 71 outputs the difference between the voltage values VI and V3 to a terminal _Tx , and the differential amplifier 72 outputs the difference between the voltage values V2 and V4 to a terminal Ty. Further, the voltage value V5 is output to the terminal Tz. Referring to the description of the structure and operation of the detection device described in §1, the voltage (V 1-V 3) obtained at terminal と な り と な り becomes the acceleration detection value in the X-axis direction, and the voltage obtained at terminal T y voltage (V 2 - V 4) becomes an acceleration detection value in the Y-axis direction, a voltage V 5 obtained to the terminal T _Z today with the understanding that the acceleration detected value of the Z - axis direction.

As described above, the acceleration in the X axis or in the {$} direction is detected by taking the difference between the two voltage values by the differential amplifier. Detection by such a difference is There are benefits that can offset such errors (eg, temperature errors). In the above-described embodiment, the acceleration that is not detected based on the difference in the acceleration of the Z-axis is described. This will be described in S4.

 The CV conversion circuits 51 to 55 and the differential amplifiers 71 and 72 described above are circuits necessary for the detection device to perform a detection operation after all. The operation test according to the present invention can be performed by further adding voltage generating circuits 61 to 65 and test switches S1 to S5 to this circuit. The voltage generating circuits 61 to 65 may be any circuits as long as they can generate a desired voltage. For example, a circuit that converts digital data output from a microcomputer into an analog signal using an A converter may be used.

Now, for example, suppose a circuit board in which test switches S1 and S3 are supplied in the circuit shown in FIG. At this time, if charges of opposite polarities are supplied from the voltage generating circuit 63 to both electrodes of the capacitive element C 3, one of the positive electrodes between the fixed electrode 13 and the displacement electrode 23 becomes positive. Since it is charged and the other is negatively charged, attractive force based on Coulomb force acts between them. Also, if charges of the same polarity are supplied from the voltage generation circuit 61 to both electrodes of the capacitive element C1, a repulsive force based on Coulomb force acts between the two. In this way, as shown in FIG. Displacement will occur. It can be seen that this is the same state as the state where the force FX in the X-axis direction acts on the point of action P. In this state, the detection voltages output to the terminals Tx, Ty, and Tz are examined, and the force It checks whether or not it has the correct detection value indicating that FX has acted. Eventually, by applying a voltage from the voltage generation circuits 61 and 63 to the capacitance elements C1 and C3, the same state as when the force FX in the X-axis direction is applied to the point of action Ρ is created. The operation test is performed by inspecting the detection voltage in the state. If the correct relationship between the applied voltage and the detection voltage is determined in advance, a quantitative operation test can be performed. In this operation test, it is not necessary to actually apply an acceleration to the operating body 30 using a vibrator or the like, but only to observe the electric signal output when an electric signal is input. The operation test is completed. Therefore, the work is much simpler than the conventional operation test, and it is suitable for mass production. To test the acceleration detection operation in the X-axis direction, apply voltages to the capacitive elements C 1 and C 3 using the switches S 1 and S 3, and test the acceleration detection operation in the Υ-axis direction. Applies a voltage to the capacitive elements C 2 and C 4 by the switches S 2 and S 4 .To test the operation of detecting the acceleration in the Ζ-axis direction, a voltage is applied to the capacitive element C 5 by the switch S 5. May be applied.

In the circuit diagram shown in FIG. 6, when the voltage generating circuits 61 to 65 are viewed from the outside, the capacitance value is not related to the generated voltage. It is desirable to keep the circuit constant. Alternatively, a circuit having a certain correlation between the generated voltage and the capacitance may be used. In the circuit, since the voltage generation circuits 61 to 65 are connected in parallel with the capacitance elements C1 to C5, if the capacitance values of the voltage generation circuits 61 to 65 fluctuate randomly, correct Operation test cannot be performed. In addition, the CV conversion circuits 51 to 55 need to detect the capacitance of the capacitance elements C1 to C5 without being affected by the voltage applied by the voltage generation circuits 61 to 65. . Figure 7 shows an example of a CV conversion circuit with such a function. The CV conversion circuit 50 shown here has a function of converting the capacitance C of the capacitive element CO into a voltage V and outputting the voltage to the terminal Tout. Note that a voltage is applied to the capacitive element CO from the voltage generating circuit 60. The CV conversion circuit 50 includes an oscillation circuit 56 and a rectification circuit 57. Oscillation circuit 56 generates an AC signal of a predetermined frequency, and supplies this to capacitive element C0. The rectifier circuit 57 is composed of resistors R 1 and R 2, capacitors C 6 and C 7, and a diode D 1. The rectifier circuit 57 converts the capacitance C of the capacitive element C 0 supplied with an AC signal to a voltage V. And output. The CV conversion circuit 50 having such a configuration can convert the capacitance C of the capacitance element CO into the voltage V without being affected by the voltage applied from the voltage generation circuit 60. Note that the circuit of FIG. 7 is shown as an example, and as a CV conversion circuit, In addition, various circuits can be applied.

Subsequently, an operation test according to the present invention will be described based on a more specific embodiment. FIG. 8 is a side cross-sectional view showing a specific test method for the + Z-axis direction force detection operation. This detection device is composed of a fixed substrate 8 ° and a flexible substrate 90. A donut-shaped groove G is dug in the bottom surface of the flexible substrate 90 °, and the portion where the groove G is dug is thinner than the other portions. In this part, it becomes flexible. The fixed substrate 80 is bonded to cover the upper surface of the flexible substrate 90 while maintaining a predetermined space on the upper surface of the flexible substrate 90. A plurality of fixed electrodes 81 force are formed on the lower surface of the fixed substrate 80 and a plurality of displacement electrodes 91 force are formed on the upper surface of the flexible substrate 90 at positions facing each other. In this embodiment, the fixed substrate 8 ° and the flexible substrate 90 are formed of a glass substrate and a silicon substrate, respectively, and the fixed electrode 81 and the displacement electrode 91 are mounted on each substrate. It is composed of an aluminum layer formed on the substrate. An insulating layer 92 such as a silicon oxide film or a silicon nitride film is formed between the flexible substrate 90 and the displacement electrode 91. In such a detection device, to achieve the same state as when the + Z-axis force is applied to the point of action P, fix it.Apply an attractive force between the electrode 8 1 and the displacement electrode 91 by Coulomb force. Just do it. Fig. 8 shows the method of applying voltage at this stage. That is, if a positive charge is applied to the fixed electrode 81 side and a negative charge is applied to the displacement electrode 91 side by the power source V, an attractive force acts between the two, and the point of action P + Operation test is possible with the Z-axis direction force applied.

 In order to make the same state as when the force in the Z-axis direction acts on the action point P, it is necessary to slightly change the structure of the detection device itself. That is, as shown in FIG. 9, a plurality of auxiliary electrodes 82 are formed on the upper surface of the fixed electrode 80. Here, a positive charge is applied to the capture electrode 82 and the flexible substrate 90 (silicon substrate) by the power supply V, and a negative charge is applied to the fixed electrode 81 and the displacement electrode 91. To give. Then, a polarization action occurs between the trapping electrode 82 and the fixed electrode 81, and a polarization action occurs between the displacement electrode 91 and the flexible substrate 90. Each part is charged. Eventually, a repulsive force due to the Coulomb force acts between the fixed electrode 81 and the displacement electrode 91, and the state is the same as when a force in the -Z axis direction acts on the point of action P.

As described above, in an operation test in which an attractive force is applied between the two, only two electrodes that directly apply a Coulomb force are sufficient, but in an operation test in which a repulsive force is applied between the two. Further, it is necessary to form auxiliary electrodes. However, since the description of the structure is complicated, the description of the auxiliary electrode is omitted in each of the following embodiments. § 3 Detector with operation test function

 In the above embodiment, the electrode pair for generating the Coulomb force and the electrode pair for forming the capacitive element are the same electrode pair. That is, an electrode pair for generating Coulomb force is a pair of a fixed electrode (11 to 15, 81) and a displacement electrode (21 to 25, 82), and an electrode for forming a capacitive element. The pair is also the same electrode pair. In this way, sharing the same electrode pair has the advantage that it is not necessary to form another electrode for the operation test, but it limits the flexibility of the test and also complicates the test circuit. There is a disadvantage that it becomes. In particular, for distribution as a commercial product, it is more convenient to separately provide a detection terminal for outputting a detection signal of a physical quantity and a test terminal for applying a voltage for a test. In the detection device shown below, a test electrode is formed in advance, and an electrode pair for generating Coulomb force and an electrode pair for forming a capacitive element are configured as separate electrode pairs. It was made.

FIG. 10a is a side sectional view of an acceleration detecting device provided with a test electrode for performing the operation test method according to the present invention. The basic structure is the same as that of the acceleration detection device shown in FIG. 1, in which a fixed substrate 10 and a flexible substrate 20 are provided to face each other, and each is fixed to the device housing 40 around the periphery. . The fixed substrate 10 is a rigid substrate, while the flexible substrate 20 is thin and flexible. On flexible substrate 20 On the surface, five displacement electrodes 21 to 25 as shown in FIG. 3 are formed. On the other hand, five test electrodes 11 t to 15 t are formed on the lower surface of the fixed substrate 10, and five fixed electrodes 11 to 15 are further formed via the insulating layer 16. . The planar arrangement of the five test electrodes 11 1 to 15 t and the planar arrangement of the five fixed electrodes 11 to 15 are the same as the electrode arrangement shown in FIG. In such a structure, the electrode pairs for forming the capacitance elements C 1 to C 5 generate a kami and Coulomb force, which is a pair of fixed electrodes 11 to 15 and displacement electrodes 21 to 25. The pair of electrodes is a pair of the test electrode 11 t to 15 t and the displacement electrode 21 to 25. Although one displacement electrode is shared, a separate electrode pair is used.

 FIG. 10b shows an example in which five test electrodes 21 t to 25 t are formed on the flexible substrate 20 side. An insulating layer 26 is formed between the test electrodes 21 t to 25 t and the displacement electrodes 21 to 25. In this case, the electrode pair for generating the Coulomb force is a pair with the test electrodes 21 t to 25 t and the fixed electrodes 11 to 15.

FIG. 11 is an example of a circuit diagram applied to a detection device having a structure as shown in FIG. 10a. When the test switch S is turned on, the voltage generating circuit 60 applies a voltage between the test electrode 11 t and the displacement electrode 21 to apply Coulomb force. As a result, the flexible substrate 20 bends, and the external force Will be in the same state as when. On the other hand, the CV conversion circuit 5 ° detects the capacitance of the capacitance element C1 constituted by the fixed electrode 11 and the displacement electrode 21 and outputs the same as a voltage V to the terminal Tout. Since the fixed electrode 11 and the test electrode 11 t are electrically insulated by the insulating layer 16, the CV conversion circuit 50 is not affected by the voltage applied by the voltage generation circuit 60. Capacitance can be detected. The external connection terminals of this detector include a common terminal that conducts to each of the displacement electrodes 21 to 25, a detection terminal that conducts to each of the fixed electrodes 11 to 15, and a test electrode 11 t to l5. It is sufficient to provide a test terminal, which is conducted for each of t. Self-diagnosis can be easily performed by checking whether a predetermined output is obtained at the detection terminal when a predetermined voltage is applied to the test terminal. FIG. 12 shows an embodiment in which the electrodes on the flexible substrate 20 are not shared but are separately provided. That is, the first test electrodes 21 t to 25 t are formed on the upper surface of the flexible substrate 20, and the displacement electrodes 21 to 25 are formed thereon via the insulating layer 26. I have. The fixed substrate 10 side is the same as in the above-described embodiment, and the fixed electrodes 11 to 15 are formed on the second test electrodes 11 1 to 15 t via the insulating layer 16. Have been. In such a structure, the electrode pairs for forming the capacitive elements C1 to C5 are a pair of fixed electrodes 11 to 15 and displacement electrodes 21 to 25. Electrode pair is the first trial A pair of the test electrode 21 1 t to 25 t and the second test position electrode 11 t to 25 t is used, and a completely separate electrode pair is used.

FIG. 13 is a side sectional view of a force detection device according to still another embodiment. A fixed substrate 110, a flexible substrate 120, a working body 130, and an auxiliary substrate 140 are provided in the device housing 100. The detector 13 31 extending from the operating body 13 ◦ is led out of a hole 101 provided in the device housing 100. In this embodiment, each of the above components is made of metal. On the lower surface of the fixed substrate 110, an insulating layer 116 is formed, and two fixed electrodes 111, 112 are formed thereon. An insulating layer 146 is formed on the upper surface of the auxiliary substrate 140, and two test electrodes 141 and 142 are further formed thereon. A detection terminal 151, a common terminal 152, and a test terminal 153 are led out of the left side of the device housing 100 (the force shown only one by one in the figure). As many as the number of electrodes are prepared). Of course, each of the terminals 151-153 is electrically insulated from the device housing 100. Each terminal 15 1-: L53 is connected to each electrode and the flexible substrate 120 by a bonding wire 16 "L-163. In this detection device, Although no displacement electrode is provided, as described above, since the flexible substrate 120 is made of metal, the flexible substrate 120 itself has an electrode function. It will be.

 In this detection device, when a force is applied to the tip of the detector 13 1, the flexible substrate 120 bends, and this flexible substrate 12 〇 (which functions as a displacement electrode) and the fixed electrode 11 1 The distance to 1, 1 1 2 changes. Therefore, the applied force can be detected based on the change in the capacitance between the detection terminal 15 1 and the common terminal 15 2. However, since only two fixed electrodes are provided in the apparatus of this embodiment, only two-dimensional forces (horizontal and vertical forces in the figure) can be detected. In order to detect the three-dimensional force, a minimum of four fixed electrodes should be provided. Now, in order to perform an operation test of this detection device, the above-described detection processing may be performed in a state where a predetermined voltage is applied between the test terminal 153 and the common terminal 152. By the action of the Coulomb force based on the applied voltage, the same state as when an external force acts on the detector 13 1 can be created. In order to perform a three-dimensional operation test, at least four test electrodes should be provided.

All of the embodiments described above are the capacitance type detection devices. The present invention is applicable not only to such a capacitance type detection device but also to a piezoelectric type detection device. FIG. 14 is a side sectional view of a piezoelectric acceleration detecting device having an operation test function according to the present invention. The fixed substrate 10 having rigidity and the flexible substrate 20 having flexibility are It is supported by the device housing 40, and is similar to the electrostatic capacitance type detection device shown in FIG. 1 in that the operating body 30 is joined to the lower surface of the flexible substrate 20. As will be described later, eight electrodes are formed on the lower surface of the fixed substrate 0 and the upper surface of the flexible substrate 20, respectively, and the piezoelectric element 45 is sandwiched between them. As the piezoelectric element 45, for example, PZT ceramics (solid solution of lead titanate and lead zirconate) can be used, and this may be inserted between both electrodes. In practice, it is preferable to manufacture electrodes by forming electrodes on the upper and lower surfaces of the piezoelectric element 45 and inserting the electrodes between the two substrates. At this time, insertion is performed in a state where a predetermined pressure is applied in the vertical direction in the figure. In this way, detection can be performed not only when the distance between the upper and lower electrodes is reduced but also when the distance between the electrodes is increased. FIG. 15 is a top view of the piezoelectric element 45, and clearly shows a planar arrangement of eight electrodes formed on the upper surface. As shown in the figure, the electrodes formed on the upper surface of the piezoelectric element 45 are made up of four fixed electrodes 18 a 18 d (hatched with diagonal lines in the figure to help visually grasp the pattern). ) And four test electrodes 19 a 19 d (similarly indicated by doting). On the lower surface of the piezoelectric element 45, four displacement electrodes 28a28d and four test electrodes 29a29d are formed in exactly the same arrangement. Cut the piezoelectric element 45 in Fig. 15 FIG. 14 shows a cross section taken along the line 14. Note that the electrode configuration is not limited to a planar—layer structure as shown in FIG. 15, but to a multilayer structure as shown in FIG. 10a, FIG. 10b, and FIG. Is also good. In such a piezoelectric detection device, a change in the distance between the pair of electrodes facing each other is detected not as a change in capacitance but as a voltage generated between the two electrodes. That is, when acceleration is applied to the acting body 30 and the flexible substrate 20 is bent, the piezoelectric element 45 receives a partial compressive force or a stretching force. . This results in a voltage at each electrode pair. By recognizing which voltage is output to which electrode pair, the direction and magnitude of the applied acceleration on three-dimensional coordinates can be detected. Unlike a capacitance-type detection device, a piezoelectric detection device cannot use both a detection electrode pair and a test electrode pair. This is because the test voltage cannot be applied to the same electrode because the voltage generated between both electrodes is directly detected. For this reason, the detection electrode pair and the test electrode pair must be separated. With the electrode arrangement shown in FIG. 15, two types of electrodes can be mixed on the same plane, and three-dimensional detection and operation tests can be performed.

The operation test can be performed as follows. For example, test electrodes 19a and 29a and 19c and 29c Applying a voltage between and applying an attractive force between 19a and 29c and a repulsive force between 19c and 29c, if this device operates normally, Predetermined voltages are generated between the fixed electrode 18a and the displacement electrode 28a and between the fixed electrode 18c and the displacement electrode 28c. By monitoring this voltage, an operation test can be performed. If a voltage is applied between the test electrodes 19b and 29b and between 19d and 29d, a test in a direction perpendicular to the test direction described above can be performed.

FIG. 16 is a side sectional view of a piezoelectric force detecting device having an operation test function according to the present invention. The device housing 200 is fixed to an industrial machine or the like using a screw hole 201, and a flexure element 250 is joined to a lower portion thereof. The flexure element 250 is made of a metal, and has a donut-shaped groove G formed on the lower surface. _C The forming portion 255 of the groove G has a small thickness and is flexible. The screw passed through the screw hole 25 1 of the flexure element 250 is screwed into the screw hole 202 of the device housing 200. A detector 260 extends on the lower surface of the center of the flexure element 25 °, and the external force acting on the tip is transmitted as momentum about the point of action P. Electrodes are formed on the upper and lower surfaces of the piezoelectric element 230 serving as the center of the device, and are sandwiched between the fixed substrate 210 and the displacement electrode flat plate 220 with a predetermined pressure. Four fixed electrodes 2 18 a to 2 18 d and four test electrodes 2 19 a to 2 19 on the upper surface d and force are formed in the same arrangement as the pattern shown in Fig.15. On the other hand, a single displacement electrode flat plate 220 is formed on the lower surface. The eight electrodes on the upper surface are fixed to the device housing 200 by the fixed substrate 210, and the displacement electrode flat plate 220 on the lower surface is fixed to the strain body 250 by the transmitter 240. It is joined to the center of the upper surface. By forming the displacement electrode flat plate 220 from a rigid thick metal plate, the force applied to the point of action P can be efficiently transmitted to the piezoelectric element 230.

 In the piezoelectric force detector having such a configuration, the displacement electrode plate 220 is used as a common electrode, and the voltage generated at the fixed electrode 218a218d is used to detect the detector 26.外 It is possible to detect the external force acting on 〇, and monitor the voltage generated on the fixed electrode 2 18 a 2 18 d while applying a predetermined voltage to the test electrode 2 19 a 2 19 d. This allows an operation test to be performed.

The embodiment shown in FIG. 17 is obtained by replacing the capacitance type force detection device shown in FIG. 13 with a piezoelectric type. In this detection device, five fixed electrodes 111 are formed in the same arrangement as the two-dimensional arrangement shown in FIG. 2 so that a three-dimensional force can be detected. In addition, four test electrodes] 4 1 to: 144 are arranged (electrode 144 is arranged behind the working body 130, and electrode 144 is arranged in front of the working body 130. Not), to be able to perform three-dimensional motion test It is. A piezoelectric element 145 is inserted between the fixed electrodes 111 to 115 and the flexible substrate 120, and an external force is applied by a voltage generated at the fixed electrodes 111 to 115. The detection power of

 In the examples shown in FIGS. 10a, 10b, 12, 13, 14, 16, 16 and 17, the operation test method according to the present invention of a fixed electrode, a displacement electrode, and a test electrode is performed. This is an embodiment provided with the minimum necessary electrodes. When an attractive force due to Coulomb force is applied between the two electrodes, only these two electrodes are sufficient, as shown in Fig. 8, but when a repulsive force is applied, as shown in Fig. 9, In addition, additional auxiliary electrodes are required. Therefore, practically, it is preferable to further provide an auxiliary electrode in the structure shown in each of the above embodiments. § 4 Example of taking the difference in the Z direction

As shown in the circuit diagram in Fig. 6, the basic acceleration detection device shown in Fig.] Makes a difference in the acceleration detection in the X-axis direction and the Y-axis direction, but differs in the Z-axis direction. No difference is made in acceleration detection. Detection by difference has a merit that the error due to the external environment such as temperature can be offset. Therefore, it is preferable to make a difference in acceleration detection in the Z direction. An embodiment for realizing this will be described below. In the embodiment whose side cross section is shown in Fig. 18, the acceleration detection in all XYZ directions is performed by taking the difference. Device. On the lower surface of the fixed substrate 310, five fixed electrodes 11 to 15 are formed in the layout shown in FIG. 19a. A doughnut-shaped groove G is dug in the lower surface of the flexible substrate 320, and an action part 321, a flexible part 32, and a fixed part 32, 23 are formed in the center, the periphery, and the periphery thereof. . On the upper surface, five displacement electrodes 21 to 25 are formed in the layout shown in FIG. 19b. The above configuration is the same as the basic configuration shown in FIG. The feature of this device is that a second fixed substrate 330 is further provided, and a displacement electrode 326 force is provided on the lower surface of the working portion 321 (and a fixed electrode is provided on the upper surface of the second fixed substrate 330). The point is that the poles 33 are formed so as to face each other.

The acceleration detection and operation test in the X-axis and Y-axis directions using this device are the same as those in the device in Fig. 1. However, acceleration detection and operation tests in the Z-axis direction are performed by the circuit shown in FIG. Here, the capacitive element C5 is composed of the fixed electrode 15 and the displacement electrode 25, while the capacitive element C6 is composed of the fixed electrode 33 and the displacement electrode 32. Is what is done. Compared with the circuit on the Z axis shown in FIG. 6, a voltage generation circuit 66 and a CV conversion circuit 56 for the capacitive element C 6 are added, and the difference between the voltage values V 5 and V 6 is calculated by the differential amplifier 73 The difference is that the calculated value is output as a detection value for the Z axis. As a result, the detection values in all XYZ directions are different. It is based on minutes and can offset effects such as temperature.

Detection based on such a difference is also advantageous in the following points. In general, the relationship between the distance d between electrodes of a capacitive element and the capacitance value C is as shown in the graph of FIG. Now, at the distance d 0, if the distance is shortened by A d from the state where the capacitance value was C 0 to d O −A d, the capacitance value increases by AC 1 and becomes C 0 + ΔC 1. Conversely, if the distance is increased by Δd to d0 + Δd, the capacitance value will decrease by ΔC2 and become CO —. Here, AC 1> AC 2. Therefore, if acceleration is detected in the Z-fist direction based only on the capacitance value of one set of capacitive elements C5, even if the absolute value is the same, the capacitance in the + Z direction and the one-Z direction is the same. The value changes differently. To deal with this, it is necessary to provide some kind of correction circuit. However, if the detection is performed based on the difference as shown in FIG. 20, such a problem does not occur. For example, in the device shown in Fig. 18, when acceleration acts in the + Z direction (upper part of the figure), the capacitance value of the capacitance element C5 changes from CO to CO + ACl, and the capacitance value of the capacitance element C6 Changes from C 0 to C ◦ — Δ C 2. Therefore, the output of the differential amplifier 73 is equivalent to AC1 + AC2. On the other hand, when the same acceleration acts in the Z direction (downward in the figure), the capacitance of the capacitor C5 changes from C0 to C room C2, and the capacitance of the capacitor C6 becomes CO power changes to C 0 + AC 1. Therefore, the output of the differential amplifier 73 is equivalent to − (Δ1 + Δ02). Thus, the same absolute value is output for the acceleration having the same absolute value.

 The embodiment shown in FIG. 22 is obtained by further adding a working body 345 and a pedestal 340 to the embodiment shown in FIG. The displacement electrode 32 6 is formed on the lower surface of the working body 345. The embodiment shown in FIG. 23 is obtained by changing the positions of the electrodes of the embodiment shown in FIG. 22. The fixed electrodes 1] to 15 are arranged on the upper surface of the fixed substrate 330 and the displacement electrodes 21 to 2 are arranged. 5 is formed on the lower surface of the working body 345, respectively, the fixed electrode 336 is formed on the lower surface of the fixed substrate 31 ', and the displacement electrode 326 is formed on the flexible substrate 320.

In each of the embodiments shown in FIGS. 18, 22, and 23, the force suitable for forming each substrate with a glass or a semiconductor (in this case, forming an insulating layer between the electrodes) is used. The acceleration detection device shown in FIG. 24 is an example suitable for being made of metal. The members 410, 420, 425, 430, 440, 450 are all made of metal. On the lower surface of the member 410, five fixed electrodes 11 to 15 are formed via an insulating layer 418. Five displacement electrodes 21 to 25 are formed on the upper surface of the member 420 via an insulating layer 428, and a donut-shaped displacement electrode 4 26 on the lower surface via an insulating layer 429. Force << formed. On the lower surface of the member 4 20, the member 4 2 5 The lower end of the member 4 25 is connected to the member 4 50 via a diaphragm 4 35. In addition, a donut-shaped fixed electrode 436 is formed on the upper surface of the member 430 via an insulating layer 438. When the acceleration acts on the member 45 °, the diaphragm 43 5 is deflected, and the member 420 is displaced via the member 425. The principle of this displacement detection is as described above.

 In the embodiment shown in FIG. 25, the acceleration detecting device shown in FIG. 24 is applied to a force detecting device, and the lower half structure is replaced with a metal member 431 (flexible substrate). ing. Based on the external force applied to the tip of the detector 4 32, the member 42 ° is displaced, and the external force is detected.

§ Other examples

As described above, the present invention has been described based on some embodiments illustrating the present invention. However, the present invention is not limited to these embodiments, and can be implemented in various other modes. For example, various arrangements of the electrodes may be considered in addition to the above-described embodiment. Further, the number of electrodes is not limited to the above embodiment. How and how many fixed electrodes, displacement electrodes, and test electrodes are to be formed is a matter that can be changed as appropriate in design. Also, for example, in the above-described embodiment, an example is shown in which the eight-electrode arrangement shown in FIG. 15 is applied to a piezoelectric detection device. Of course, the arrangement can also be applied to a capacitance type detection device. Rather than adopting a structure in which the electrodes are stacked in two stages as in the detection devices shown in Figs. 10 and 12, the arrangement of the electrodes in one layer as shown in Fig. 15 simplifies the manufacturing process and enables mass production. It is rather desirable for production.

In the above-described embodiment, an example in which a metal layer of aluminum or the like is formed on a semiconductor substrate and this is used as an electrode is mainly described, but the electrode may be formed by any method. . For example, an impurity diffusion region can be formed in a semiconductor substrate and used as an electrode. Further, if the fixed substrate and the flexible substrate are formed of metal, the substrate itself can be used as an electrode. Therefore, in the present invention, the electrodes need not necessarily be separate from the substrate. Further, in the above-described embodiment, the acceleration detecting device and the force detecting device have been described. However, if the acting body is made of a magnetic material, a force based on magnetism can be detected. That is, the present invention is equally applicable to a magnetic detection device. INDUSTRIAL APPLICABILITY The operation test method according to the present invention can be widely applied to a force detection device, an acceleration detection device, and a magnetic detection device that detect a physical quantity by using a change in the distance between electrodes. is there. Also, this The detection device having the function of performing the operation test can perform the operation test by a simple method, and can be used with high reliability in practical use. Therefore, applications to automobiles and industrial robots can be expected.

Claims

The scope of the claims 1. A displacement electrode (21 to 25) supported so as to be displaceable by the action of an external force, and a fixed electrode (1:! ~) Fixed to the device housing (40) at a position facing the displacement electrode 15) and detecting means (51 to 55) for extracting a change in the distance between the two electrodes as an electric signal, and detecting the physical quantity corresponding to the external force as an electric signal. Operation test method,  A predetermined voltage is applied between the fixed electrode and the displacement electrode, and the displacement electrode is displaced by a Coulomb force generated based on the applied voltage. An operation test method characterized by testing the operation of the detection device by comparing a signal with the applied voltage. 2. Displacement electrodes (2 1 to 25) supported so as to be displaceable by the action of an external force, and fixed electrodes (1:! ~) Fixed to the device housing (40) at positions facing the displacement electrodes. 15) and detection means (51 to 55) for extracting a change in the distance between the two electrodes as an electric signal, and a detection device for detecting a physical quantity corresponding to the external force as an electric signal. An operation test method, At the position facing the displacement electrode, the device housing A fixed test electrode (11 t to 15 t) is further provided, a predetermined voltage is applied between the test electrode and the displacement electrode, and the displacement is caused by the Coulomb force generated based on the applied voltage. An operation test method, comprising: displacing an electrode; and comparing an electric signal detected by the detection means in the displaced state with the applied voltage to test operation of the detection device. 3. Displacement electrodes (21 to 25) supported so that they can be displaced by the action of external force, and fixed electrodes (11 to 1) fixed to the device housing (40) at a position facing the displacement electrodes. 5) and detecting means (51 to 55) for extracting a change in the distance between the two electrodes as an electric signal, and a detecting device for detecting a physical quantity corresponding to the external force as an electric signal. An operation test method, A test electrode (21 t to 25 t) supported so as to be displaceable together with the displacement electrode at a position facing the fixed electrode is further provided, and a predetermined electrode is provided between the test electrode and the fixed electrode. A voltage is applied, the displacement electrode is displaced by a Coulomb force generated based on the applied voltage, and an electric signal detected by the detection means in the displaced state is compared with the applied voltage, whereby the detection device is provided. An operation test method characterized by testing the operation of a device. 4. Displacement electrodes (2 1 to 25) supported so that they can be displaced by the action of an external force, and fixed electrodes (1 1-1) fixed to the device housing (40) at positions facing the displacement electrodes. 5) and detecting means (51 to 55) for extracting a change in the distance between the two electrodes as an electric signal, and a detecting device for detecting a physical quantity corresponding to the external force as an electric signal. An operation test method,  A first test electrode (211: to 25 t) supported so as to be displaceable together with the displacement electrode, and a second test electrode fixed to the device housing at a position facing the first test electrode. A test electrode (11 t to 15 t), and a predetermined voltage is applied between the first test electrode and the second test electrode, and a voltage is generated based on the applied voltage. The displacement electrode is displaced by a cloning force, and the operation of the detection device is tested by comparing the electric signal detected by the detection means with the applied voltage in this displaced state. Test method. 5. A fixed portion fixed to the device housing (40), an operating portion receiving a force based on the action of an external physical quantity, and a flexible portion formed between the fixed portion and the operating portion. A flexible substrate (20) having a flexible portion; A fixed substrate (10) fixed to the device housing so as to face the flexible substrate; Displacement electrodes (21 to 25) formed at positions where displacement occurs due to the radius of the flexible substrate;  Fixed electrodes (11 to 15) fixed by the fixed substrate and formed at positions facing the displacement electrodes;  A test electrode fixed to the apparatus housing at a position facing the displacement electrode and electrically insulated from the fixed electrode;  Detecting means (51 to 55) for outputting a change in capacitance generated between the displacement electrode and the fixed electrode as an electric signal;  Voltage applying means (61 to 65) for applying a predetermined voltage between the test electrode and the displacement electrode;  With  An operation test is performed by detecting a force acting on the action section based on the electric signal output by the detecting means, and comparing the electric signal output by the detecting means with the applied voltage applied by the voltage applying means. A physical quantity detection device characterized in that the physical quantity can be measured. 6. A fixed portion fixed to the device housing (40), an operating portion that receives a force based on the action of an external physical quantity, and a flexible portion formed between the fixed portion and the operating portion. A flexible substrate (20) having a flexible portion; Fixed to the device housing so as to face the flexible substrate. Fixed substrate (1 ◦)  A displacement electrode (21 to 25) formed at a position where displacement occurs due to the radius of the flexible substrate;  Fixed electrodes (11 to 15) fixed by the fixed substrate and formed at positions opposed to the displacement electrodes;  A test electrode (211: to 25t) which is displaced together with the displacement electrode at a position facing the fixed electrode, and is electrically insulated from the displacement electrode;  Detecting means (51 to 55) for outputting a change in capacitance generated between the displacement electrode and the fixed electrode as an electric signal;  Voltage applying means (61 to 65) for applying a predetermined voltage between the test electrode and the fixed electrode;  俯 ·  An operation test is performed by detecting a force acting on the action section based on the electric signal output from the detecting means and comparing the electric signal output from the detecting means with the applied voltage applied by the voltage applying means. A physical quantity detection device characterized in that it can be performed. 7. A fixed portion fixed to the device housing (40), an operating portion receiving a force based on the action of a physical quantity from the outside, and a flexible portion formed between the fixed portion and the operating portion. A flexible substrate (20) having a flexible portion; A fixed substrate (10) fixed to the device housing so as to face the flexible substrate;  A displacement electrode (21 to 25) formed at a position where displacement occurs due to deflection of the flexible substrate;  Fixed electrodes (11 to 15) fixed by the fixed substrate and formed at positions facing the displacement electrodes;  A first test electrode (21 t to 25 t) formed at a position where the flexible substrate bends based on its own displacement and electrically insulated from the displacement electrode;  A second test electrode (11 t to 15 t) fixed to the device housing at a position facing the first test electrode and electrically insulated from the fixed electrode;  Detecting means (51 to 55) for outputting a change in capacitance generated between the displacement electrode and the fixed electrode as an electric signal;  Voltage applying means (6 1 to 65) for applying a predetermined voltage between the first test electrode and the second test electrode;  With An operation test is performed by detecting a force acting on the action section based on the electric signal output from the detecting means and comparing the electric signal output from the detecting means with the applied voltage applied by the voltage applying means. A physical quantity detection device characterized in that it can be performed. 8. A fixed portion fixed to the device housing (200), an action portion receiving a force based on the action of a physical quantity from the outside, and a flexible portion formed between the fixed portion and the action portion. A flexible substrate having the property; a flexible substrate (250) having:  A fixed substrate (210) fixed to the device housing so as to face the flexible substrate;  A displacement electrode (220) arranged at a position where displacement occurs due to the bending of the flexible substrate;  A fixed electrode (218a to 218d) fixed by the fixed substrate;  A piezoelectric element (230) that is disposed so as to be sandwiched between the flexible substrate and the fixed substrate, converts a pressure applied by the two substrates into an electric signal, and outputs the electric signal to the two electrodes; A test electrode (2l9a to 2l9d) fixed to the device housing at a position facing the electrode and electrically insulated from the fixed electrode;  Voltage applying means for applying a predetermined voltage between the test electrode and the displacement electrode;  With An operation test is performed by detecting a force acting on the acting portion based on the electric signal output from the piezoelectric element and comparing the electric signal output from the piezoelectric element with an applied voltage applied by the voltage applying means. A physical quantity detection device characterized in that it can be performed. 9. A fixed portion fixed to the device housing (200), an action portion receiving a force based on the action of a physical quantity from the outside, and a flexible portion formed between the fixed portion and the action portion. A flexible substrate having the property; a flexible substrate (250) having:  A fixed substrate (210) fixed to the device housing so as to face the flexible substrate;  A displacement electrode (220) arranged at a position where displacement occurs due to the bending of the flexible substrate;  A fixed electrode (218a to 218d) fixed by the fixed substrate;  A piezoelectric element (230) that is disposed so as to be sandwiched between the flexible substrate and the fixed substrate, converts a pressure applied by the two substrates into an electric signal, and outputs the electric signal to the two electrodes; A test electrode displaced with the displacement electrode at a position facing the test electrode, and a test electrode electrically insulated from the displacement electrode;  Voltage applying means for applying a predetermined voltage between the test electrode and the fixed electrode;  With An operation test is performed by detecting a force acting on the acting portion based on the electric signal output from the piezoelectric element and comparing the electric signal output from the piezoelectric element with an applied voltage applied by the voltage applying means. A physical quantity detection device characterized in that it can be performed. 10. A fixed portion fixed to the device housing (40), an action portion receiving a force based on the action of a physical quantity from the outside, and a flexible portion formed between the fixed portion and the action portion. A flexible substrate having the following properties:  A fixed substrate (10) fixed to the device housing so as to face the flexible substrate;  A displacement electrode (28a to 28d) disposed at a position where displacement occurs due to the radius of the flexible substrate;  Fixed electrodes (18a to l8d) fixed by the fixed substrate;  A piezoelectric element (45) that is disposed so as to be sandwiched between the flexible substrate and the fixed substrate, converts a pressure applied by the two substrates into an electric signal, and outputs the electric signal to the two electrodes; A first test electrode (29 a to 29 d) formed at a position that causes a radius in the flexible substrate based on the displacement electrode and electrically insulated from the displacement electrode;  A second test electrode (19 a to 19 d) fixed to the device housing at a position facing the first test electrode and electrically insulated from the fixed electrode;  Voltage applying means for applying a predetermined voltage between the first test electrode and the second test electrode;  With The force acting on the acting portion is detected based on the electric signal output from the piezoelectric element, and the output of the piezoelectric element is detected. An apparatus for detecting a physical quantity, characterized in that an operation test can be performed by comparing an applied electric signal with an applied voltage applied by the voltage applying means. 1 1. A fixed part that is fixed to the device housing, an operating part that receives a force based on the action of an external physical quantity, and a flexible member that is formed between the fixed part and the operating part. A flexible substrate (320) having a  A first fixed substrate (3110) fixed to the device housing so as to face the first surface of the flexible substrate;  A second fixed substrate (330) fixed to the device housing so as to face the second surface of the flexible substrate; and a first displacement formed on the first surface of the flexible substrate. Electrodes (2 1 to 25) and  A second displacement electrode (326) formed on a second surface of the flexible substrate;  A first fixed electrode (11 to 15) fixed by the first fixed substrate and formed at a position facing the first displacement electrode;  A second fixed electrode (336) fixed by the second fixed substrate and formed at a position facing the second displacement electrode; A change in capacitance between the first displacement electrode and the second fixed electrode, and a change in the capacitance between the second displacement electrode and the second fixed electrode. Detecting means (56) for outputting a change in the capacitance between the fixed electrode and the electric signal as an electric signal;  With  A physical quantity detection device characterized by detecting a force acting on the action section based on an electric signal output by the detection means.